is this site full of engineers?
almost every thread on here ends up suggesting some super over engineered setup thats bordering rediculous for a medial task
rims tubes work, they work with a false bottom with a smaller diameter than the pot/keg (within reason) and dont channel. i know this because ive actually used said setup.. a lot..
herms will never have the response, ramp times or accuracy of rims purey by the thermal mass in the heat exchanger and if you recirculate until the mash bed is set and starts to clear a little (5 mins or so anyway) before starting the PID you wont scorch anything